This invention relates to a forming method of a foam board, particularly to one having a foam board wrapped up by a hard plastic upper plate and a hard plastic lower plate so as to elevate the rigidity and safety of the foam board.
A conventional foam board is a plastic foam body made of ethylene vinyl acetate copolymer (EVA) or polyethylene resins, light and having good buoyancy as well as easy to be carried about, and able to be made into a large area with low cost so it is widely employed to make a surfboard, a skiing board, a grass skateboard, a sand skateboard or the like for various open-air exercises.
However, a foam board is substantially a foam body with high magnifying power and cannot endure grinding so it is liable to be damaged in case of rubbing against a sandy ground or a stony ground. In view of this property, a hard bottom plate is additionally employed to glue on the bottom side of a foam board, but the top surface and the side edge of the foam board has no hard plate for protection. Thus, when sliding fast on a steep slope, a grass skateboard or a sand skateboard will most likely be bumped or overturned, and its edge will be damaged first. In other words, if the edge of a foam board is not strong enough, it cannot bear a quick rushing force to protect a user, and if the whole body of a foam board is not rigid enough, it is liable to bend, resulting in overturning.
Besides, the tip and the peripheral edge of a foam board are mostly turned up in an arcuate shape in order to let the foam board slide smoothly and controlled alertly. Further, its peripheral edge is cut in an arc-shape for the convenience of gripping and sliding. In this case, it is not easy to manually glue a hard plate on the peripheral edge of the foam board, and even if a hard plate is attached on the peripheral edge of the foam board, it cannot fixedly be glued with the hard bottom plate of the foam board, consequently easy to cause damage at the contacting edge between the hard side plate and the hard bottom plate.
The main objective of the invention is to offer a forming method of a foam board, provided with a hard plastic top plate and a hard plastic bottom plate respectively on and under a foam board and having the circumferential edges of the hard plastic top and the bottom plate automatically bend and extend to stick on the peripheral edge of the foam board and make up an integral side edge to wrap up the entire foam board to increase the rigidity and security of the foam board.
Another objective of the invention is to offer a forming method of a foam board by means of a mold in which a net layer, a hard plastic bottom plate, a foam board, and a hard plastic top plate are laid on one another orderly. Further, the hard plastic top plate or the hard bottom plate has a peripheral edge bending downward or upward and extending to stick around the edge of the foam board. Thus all of the materials are all formed integral into a finished foam board with one round of processing, elevating producing efficiency and having effect of forming a foam board without using glue or the like.